Department Seminar of Sabrina Kalenko- Effects of internal waves and circulating currents on stratification in a pool
Effects of internal waves and circulating currents on stratification in a pool
Monday February 10th 2025 at 14:00
Wolfson Building of Mechanical Engineering, Room 206
Abstract:
This study explores internal resonant standing gravity waves within a rectangular basin. This study was motivated by observation of such waves in the cooling reservoir of an open-pool-type nuclear reactor. In that system, stratification results from addition of a hot water layer at the upper part of the pool, Geva et al. (2021) reported on self-excitation of standing internal waves within the thermocline between the layers with high and low temperatures.
The research focuses on characterizing the resonant oscillation modes of the system using theoretical models. Experiments were carried out in a narrow rectangular basin that allow 2D approach; surface and/or internal waves were excited by a computer-controlled oscillating cylinder. The density control was attained by adding salt (MgCl2) to water resulting in a mixed layer with a density gradient (pycnocline). Measurements based on video shadowgraphy were conducted to reveal the fundamental characteristics of both surface and internal waves in a closed basin, followed by more detailed investigations into the wave structure using simultaneous Particle Image Velocimetry (PIV) and Background Oriented Schlieren (BOS) techniques. The accumulated extensive quantitative experimental data enable the characterization of the resonant conditions, and allow identification of diverse spatial and temporal wave modes generated by both linear and nonlinear mechanisms. The results show good agreement with theoretical models.
Bio:
Sabrina Kalenko earned her B.Sc. and M.Sc. degrees from the School of Mechanical Engineering at Tel Aviv University. During her M.Sc. studies, she focused on the turbulence interaction of high Stokes number irregularly shaped particles in the accelerating flow of a rocket-engine model, under the supervision of Prof. Alex Liberzon. After completing her M.Sc. degree, she joined the Soreq Nuclear Research Center as a Ph.D. student at Tel Aviv University, under the supervision by Prof. Lev Shemer and Dr. Efi Zemach.
